ΔE 14.4, fair: the same colour family, but not a straight swap. Beasty Brown is much more muted than Light Rust.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Beasty Brown is much more muted than Light Rust.
The same difference applies the other way round: Light Rust is much more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Light Rust on the colour wheel See Beasty Brown on the colour wheel
All matches: Light Rust equivalents · Beasty Brown equivalents